Case Studies
ITC- IRC, Bangalore
Indian Institute of Science, Bangalore
Forbes-Gokak Mills, Gokak
Wells Fargo

        ITC Ltd.

          IRC (Integrated Research Center).

Client:  ITC Ltd. IRC (Integrated Research Center).
Location:  Peenya, Bangalore.
Year:  1989-90
PROJECT: Trouble shooting problems in steam distribution of a newly commissioned tobacco curing R&D unit.
Letter of Appreciation :  View Here

Background:

ITC Ltd. had set up an Integrated Research Centre for tobacco curing for developing new and better processing of different type tobacco grown in different growing areas. The processes thus developed are transferred to their production units. Tobacco curing is basically a process where predominantly steam is used for curing the tobacco.

After the unit was commissioned it was found that the steam pressures were not adequate and all the equipments suffered from lower steam pressures and temperatures. As a result the experiments were not successful and time required used to be unacceptably long.

ENERTECH was invited to carry out a study of the plant and recommend measures to improve the operations.

A study was carried out with trials and various measurements.

The findings and recommendations are given below: 

Steam generators: 

One no. Steam generator, 600 kg/hr Model: Revomax NIBR. Working pressure- 10.34 kg/cm2 LDO fired.

Steam consuming equipment: 

  • Group I: Primary cylinder and casing cylinder, one each.

  • Group II: Steaming cylinder and Air Drier, one each

  • Group III: Apron cylinder and Burley condition cylinder, one each.

However, only one group of equipment will run at any given time.

OBSERVATIONS:

  • The model of steam generator selected was not found to be correct. The instant type of boilers installed do not have storage space for steam and pass (three pass) through the heating cfuel when water is converted into steam. The disadvantage of such boiler is that they produce very wet steam instead of dry saturated steam. On an average steam will contain 15% moisture, thus reducing the heat content. As a result, by the time steam traverses through the distribution network it becomes further wet and loses heat and pressure. This was the reason for why steam pressure at the inlets of various equipment was observed to be less than required.

  • It was observed that the equipment (air drier) which required the highest temperature (and therefore pressure) was installed at the end of the pipe line, at around 300 metres from the boiler. As a result, there used to be only hot water being supplied instead of steam.

  • The steam consuming machineries were fitted with Thermodynamic traps, instead of ball float operated traps, which are continuous discharge type and correct ones.

  • Main lines did not have any steam traps to drain out moisture and this was getting carried over to machines.

  • Cylinder driers did not have any automatic air vents to allow air trapped inside.

  • The inlet and outlet pipe of Steam Pressure reducing valve(PRV) installed on the Drier cylinder was found to be of same size of 40 mm dia.

  • It was observed that steam tapping from the main lines was taken from the bottom of the line instead from the top.

Recommendations

  • To install a moisture separator on the outlet of steam boiler. This will remove most of the moisture carried by the steam.

  • Install moisture drain traps on the main line.

  • To shift the air drier nearer to the boiler room so that steam at highest temperature and pressure is made available.

  • Replace TD(Thermodynamic traps) by FT (Float traps) on continuous discharge machines, and install Automatic air vents(AVs) on the outlets of condensate discharge points of machineries.

  • Increase the outlet pipe of PRV from 40 mm dia to 65 mm dia.

  • In addition it was recommended to install one more 600 kg/hr steam boiler since the present capacity of one boiler is not adequate to meet the demand (due to poor quality of steam). Also, it was decided to install an after heater to remove the excessive moisture content in the steam since the instant boilers give out very wet steam.

  • On implementation of the above measures ITC were able to operate the plant as per their original design. (Letter of commendation)